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194 Cards in this Set
- Front
- Back
What is the function of the heart?
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to pump the blood through 120,000 km of blood vessels
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What must both sides of the heart do , to ensure adequate blood flow to or from all body tissues?
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contract or relax their chambers at the same moment
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define the term vascular
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relating to or containing blood vessels
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define the term perfusion
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supplying the body system with oxygenated blood
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define the term cardiology
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the study of the heart and heart disorders
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What does a "closed circuit of blood flow" mean?
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blood is always enclosed in the heart or blood vessels
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What are the two separate circuits of blood flow that the heart has?
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systemic circuit(everywhere else), pulmonary circuit (heart and lungs)
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which blood vessels contain higher pressured blood? (veins or arteries)
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arteries, because the need high pressure to push to capillary beds
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Where is the heart located?
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mediastium of the left side of the thoracic cavity enclosed by a pericardial sac
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What fraction of the heart is to the left of mid-line of the thoracic cavity?
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2/3
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Where is the apical pulse palpated?
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5th inter-coastal space
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Describe the "fibrous pericardium" , what is its function?
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Outer tough layer made of DICT, often covered in fat. Functions to protect heart, anchors heart to diaphragm within the thoracic cavity, prevents sudden overfilling of heart
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Describe "serious pericardium"
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2 layers of serous membrane separated by a serous cavity containing serous fluid
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Where is the serious pericardium located?
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located in fibrous pericardium
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what is the function of serious pericardium?
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helps protect and anchor the heart within the thoracic cavity, provided frictionless surface for the heart to pump freely within the sac
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What are the 3 parts that make up serious pericardium?
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parietal pericardium, visceral pericardium, pericardial cavity filled with pericardial fluid
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What is the inner layer of the seriuos membrane called?
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viserceral pericardium aka endocardium
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which layer of the heart does the visceral pericardium form?
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outer layer of heart
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What is visceral pericardium (aka endocardium) physically attached too?
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myocardium (heart muscle)
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what is the outer layer of the serious membrane called?
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parietal pericardium
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Where is the pericardial cavity located?
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parietal and visceral layer
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What is the function of the pericardial fluid?
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protects rapidly beating heart by reducing friction, thus allows the heart to beat freely
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what is pericarditis?
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inflammation of the pericardium
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What is pericardial rub?
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sound heard when heart rubs again pericardial membrane
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What is pericardial infusion?
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build up of fluid within the pericadial sac, leads to compression of the heart , can be lethal
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what are the three layers of the heart wall?
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epicardium, myocardium,endocardium
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What layer of the heart wall is described as the "thin, transparent outermost layer"
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epicardium
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What is the function of the epicardium?
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allows heart to pump freely without friction
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What is the epicardium made out of?
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serous membrane
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Which layer of the heart is described as "the middle layer, bulk of heart wall, made of bundles of cardiac muscle"?
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myocardium
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What is the function of the myocardium? (include the function of the intercalated disks)
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involuntary contraction of the heart to pump blood, presence of the intercalated disks help anchor the muscle cells together allowing the heart to contract and create a synchronous heart beat.
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What is the histology of the cardiac muscle that makes up the myocardium?
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branch, central nucleus, striated, intercalated discs
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What is the inner most layer of the heart called?
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endocardium
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What type of cells is endocardium made of?
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endothelial cells and a thin layer of connective tissue
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What is endothelium and its function in the endocardium? Besides the chambers of the heart , what other structure does it line?
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simple squamous epithelium. Provides a smooth lining for blood flow through the heart chambers.heart , blood vessels, lymphatic vessels, heart valves
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What are the two upper chambers of the heart called that are nicknamed "the recievers"
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atria
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What are the two lower chambers of the heart that are nicknames "the pumpers"?
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ventricles
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In blood flow terminology, what do drains usually imply?
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deoxygenated blood
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In blood flow terminology what does "supplies" usually apply?
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oxygenated blood
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Why is the heart termed a "double pump"?
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each side of the heart pumps blood to a different region of the body , thus the heart acts as a double pump
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Why does the artia have a thinner myocardium then the ventricles?
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the atria has a thinner myocardia because they only need to pump blood a short distance, ventricles have a thick myocardia because they must pump blood a further distance
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What is the function of the auricles?
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helps to slightly increase blood recieving capacity of each atria
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Where are the pectinate muscles located?
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in the walls of the artium (rough muscular ridges)
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What is the oval depression called in the Interatrial septum?
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fossa ovalis
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What is the fossa ovalis a remenent of?
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foramn ovale
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What was the function of the foramen ovale?
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its an opening between the 2 atria in a fetal heart.In fetal circulation the foramen oval allows blood to bypass the non functioning fetal lungs.
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What is the most common cause of Atrial Septum Defect (ASD)?
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congential patency of the foramen ovale
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What are the 3 large vessels that deliver deoxygenated blood to the right atrium?
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superior vena cava - drains structures superior to the heart, Inferior vena cava- drains structures inferior to the heart, coronary sinus- drains myocardium
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Where does the left atrium recieve oxygenated blood from?
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the 4 pulmonary veins (2 R and 2 L)
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What are the muscular ridges inside the ventricles called that help to direct blood flow?
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trabeculae carnae
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What is Ventricular Septal Defect?
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congenital defect cause by incomplete formation of the interventricular septum
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What is the strongest oxygenated vessel in the body?
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aorta
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Which ventricle contains the thickest myocardium? why?
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left ventricle, because it pumps blood the furthest distance ,
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What is the small blood vessel called in a fetus that shunts blood from the pulmonary trunk into the aorta , bypassing the non functioning lungs?
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ductus ateriosus
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At birth pressure changes cause the ductus ateriosus to close , what does it form?
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ligamentum arteriosum
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Normally at birth pressure changes cause the ductus arteriosum to close and change into the ligamentum arteriosum. If the ductus arteriosum remains open what is it called?
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patent ductus arteriosum (a congenital defect)
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What does the fibrouse skeleton of the heart function for?
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attachement sites or heart valves and cardiac muscles, prevent overstretching of heart valves during the contraction phase, act as electrical insulators to prevent uncontrolled spread of conduction signals across cardiac muscle cells in atria and ventricles
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What is the fibrous skeleton of the heart made up of?
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4 rings of dense connective tissue
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Why do valves open and close?
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in response to pressure changes as the heart contracts and relaxes
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What are the two types of heart valves?
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atrioventricular and semilunar
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Where are the atrioventricular valves located?
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between atria and ventricles
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what are the 3 main parts of an atrioventricular valve?
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cusps, chordae tendineae, papillary muscles
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what are cusps in an antrioventricular valve made of?
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DICT covered with endothelium
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What are the Chordae tendineae in an atrioventriuclar valve? What do they function for?
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tiny tendons which attach cups to papillary muscle
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What are papullary muscles found in atrioventricular valves? What do they function for?
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extension of myocardium on the ventricles, functions to anchor chorae tendineae
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What is the function of the Atrioventricular valve?
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prevents backflow of blood from the ventricles back into the atria
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Explain how the atrioventriuclar valves prevent backflow?
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prevent backflow by contraction of the papillary muscles tightening chodae tendineae which prevent the valve cups from everting (turning inside out)
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Explain the pressure when an atrium contracts?
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when an atrium contracts interatrial pressure is greater that interventricular pressure , this causes the valves to open fulls and blood flows into the ventricles
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Explain how the interventriuclar valves close after blood has flown from the atria to the ventrice
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after blood has flown from the atria to the ventricle, the ventricle contracts and the ventricular pressure causes the blood to push against the inferior surface of the valve cusps pushing the valve closed
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What forces the blood through a semilunar valve and into the corresponding artery in a ventricle?
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increased intraventricular pressure
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Where are the semilunar valves located?
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located between a ventricle and a major artery leaving the ventricle
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describe the structure of a semilunar valve
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made of , 3 cusps each with a half moon shape , cusps "catch" the blood as it backflows , when cusps are full the valves are closed
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What does the work trunk mean , ex. Pulmonary trunk?
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really big artery
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How does the semilunar valves close?
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when the ventricle relaxes the interventricular pressure becomes less than the intrarterial pressure and the blood begins to flow back into the ventricle causing the cusps of the semilunar valve to fill with blood, closing the valve
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How does the semilunar valves open?
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When the ventricle contracts the intraventricular pressure is greater than the intrarterial pressure causing blood to flow into the artery
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What is ausculation?
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listening to heart sounds with a stethescope
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what causes the heart sounds heard during auscultation?
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turbulent blood flow as valves close
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what are the S1- lubb sounds heard during auscultation?
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deep, booming sound during closing of AV valves
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What are the S2- dubb sounds heard during ausculation?
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sharp, high pitched sound during closing of semilunar valves
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What is heart murmur?
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abnormal heart sound due to an abnormal valve function it could be caused by valve prolapse or valve regurgitation
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Where is the trabeculae carneae located? what is its fucntion?
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located in the ventricle, helps direct blood flow
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What are the two main circuits of blood flow?
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systemic circulation, pulmonary circulation
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What is systemic circulation?
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pumps oxygenated blood recieved from the lungs to all systemic body tissues except the aveoli
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What is pulmonary circulation?
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pumps deoxygenated blood recieved from the body cells to the lungs to become oxygenated
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How does oxygenated blood enter the left atrium of the heart?
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4 pulmonary veins
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What is coronary circulation?
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a special subscribt of the systemic circulation that supplies oxygenated blood to the myocardium and removes waste deoxygenated blood
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What are the first vessels to branch of the aorta?
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coronary arteries
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What does every cardiac muscle have , due to the fact that the myocardium is so well vascularized?
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every cell has its own cappillaries
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What is the function of the Purkinje fibers?
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stimulate all of the individual cardiac muscle cells to contract
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Which fibers must be stimulated before the ventricles contract?
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Purkinje fibers
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Describe the direction of contraction of the heart chambers?
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atria contract from superior to inferior, ventricles contract from inferior to superior
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What type of respiration do Cardiac muscle
cells use to produce most of their ATP? |
aerobic respiration
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What are the 4 steps involved in Cardiac Action potential formation?
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Depolarization, Plateau, Re-polarization, Refractory period
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What happens during the depolarization phase?
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fast voltage gated Na+ channels open, Na+ enters the cell causing rapid depolarization from resting membrane potential of -90 mV
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What happen during the "plateau" phase in cardiac action potential formation?
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slow-volatage gated calcium channels open, and calcium enters cytoplasm through ECF and the sarcoplasmic reticulumn (SR)
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How much longer does it take for cardiac muscle cells to contract compared to skeletal muscles?
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it takes skeletal muscle cells 250x longer to contract than cardiac muscle cells
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What happens during the "re-polarization" phase in cardiac action potential formation?
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voltage-gated K+ channels open. K+ leaves the cell and the cardiac muscle cells return to RMP
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What happens during the "(absolute) refractory period" phase in cardiac action potential formation?
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it is the time during witch a secondary muscle contraction cannot occur.
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Why is the refractory period longer for cardiac muscle cells than skeletal muscle cells?
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to revent tetany ( a sustained muscle contraction ie. cardiac arrest)
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What is an electrocardiography?
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recording of the electrical activity of the heart
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during depolarization , what are the cardiac muscle cells stimulated to do?
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contract
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during re-polarization why do the cardiac muscle cells return to resting membrane potential to allow them to relax?
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allow them to relax
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what must occur before contraction of the heart chambers?
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depolarization
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what must occur before relaxation of the heart chambers?
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repolarization
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What is depolarization? describe the electrolytes in your answer
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fast volatage-gated Na+ channels open. Na+ enter the cell causing rapid depolarization from resting membrane potential (RMP) of -90 mV
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What is a "plateau" in cardiac action potential formation? Include electrolytes in your answer
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slow voltage-gated Ca+ channels open and Ca+ enters cytoplasm from the extracellular fluid (ECF) and the sarcoplasmic reticulum (SR).
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how much longer does it take for cardiac muscles to contract than skeletal muscles?
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250x longer
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what is re-polarization? explain including electrolytes
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voltage gated k+ channels open k+ leaves the cell and cardiac muscle cells return to RMP
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What is the refractory period?
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time during which a second contraction cannot occur
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Why is there a longer refraction period for cardiac muscle cells than skeletal muscle cells?
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to prevent tetany
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what is tetany?
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a sustained muscle contraction
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What does the P wave on an EKG consist of?
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time during which depolarization reaches SA node, SA node fires and stimulates the atria to contract
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What are the components of the conduction system involved in the QRS complex?
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av node --> bundle of HIS --> Bundle branches --> Purkinje fibers
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What is stimulated to contract when depolarization reaches the purkinje fibers?
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ventricles are stimulated to contract
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Why is atrial re-polarization not visible on an EKG during the QRS complex ?
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because it is masked by larger electrical activity occurring in the ventricles, so atrial repolarization does occur simultaneously
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What does the T Wave on a EKG represent?
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time during which ventricles are returning to RMP so that they can relax
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What is the cardiac cycle by definition?
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all of the cardiac events associated with one heart beat
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What does the cardiac cycle include?
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electrical events, mechanical events, opening and closing of heart valves, direction of blood flow
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How long does the cardiac cycle last when the heart rate is at 75 beats/min
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0.8 seconds
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When can chambers only fill with blood?
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when they are relaxed (diastole)
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How long does atrial systole last?
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about 0.1 seconds
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what state are the ventricles in during atrial systole
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relaxation (diastole): fill rapidly
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what percentage of ventricles fill passively ?
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70 %
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As atria fully contract, what does the atrial pressure become compared to the ventricular pressure?
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greater than the ventricular pressure
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As the atrial pressure becomes greater than the ventricular pressure and the Av valves are fully pushed open , what remaining percentage of atrial blood enters the ventricles? What is this percentage of atrial blood called?
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30% , atrial kick
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What does the "End diastolic volume" mean?
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volume of blood/ ventricle at end of ventricular relaxation phase, it should equal the maximum fill per heart beat.
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what wave indicates the onset of ventricular systole?
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QRS wave
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How long does ventricular systole last for?
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0.3 sec
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What is an isovolumetric contraction?
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for a moment all 4 valves are closed
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When does the first heart sound occur (S1:Lubb)
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when ventricle pressure is greater then atrial pressure; Av valve closes
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what valves open when ventricular pressure is greater than arterial pressure?
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semilunar valves open
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when does the S2:dubb (2nd heart sound) occur?
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as arterial pressure is greater than ventricle pressure, blood begins to flow backwards (towards ventricles) and semilunar valves fill with blood and close
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What is the End Systolic Volume (ESV)?
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volume of blood remaining in a ventricle at the end of ventricular contraction
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What is "stoke volume/ejection volume"?
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End Diastolic Volume - End Systolic volume
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What is the average ejection fraction?
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70 mL ( 130 ml- 60 ml = 70 ml) * NOTICE THAT THE VENTRICLES ARE NEVER EMPTY
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What is the Quiscent (relaxation) period?
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the time between 2 heart beats
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How long does the relaxation period last for a person with a HB= 75 bpm?
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0.4 seconds (decreased time with increased HR)
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During the relaxation period what are all 4 chambers doing, and what position are all 4 heart valves?
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all 4 chambers a relaxed (Atrial and ventricular diastole), all 4 heart valves are closed (Isovolumetric relaxation)
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what occurs at the end of the relaxation period?
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atria are passively filling with blood, once atria pressure is greater than ventricular pressure , the AV valves partially open and blood passively flows in ventricles (gravity), atria depolarize then begin to contract ... P WAVE
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What is the definition of Cardiac Output?
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volume of blood pumped by a ventricle per minute (minute volume)
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What two variable directly measure and regulate cardiac output (CO)
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stroke volume and heart rate, stroke volume = volume of blood pumped by a ventricle/heart beat, heHart rate = # of heart beats/ min
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What is the formula to know when measuring Cardiac output?
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stroke volume X heart rate = cardiac output
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What is Cardiac Output a major direct regulator of? What is the exception?
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Blood pressure, an increase or decrease in stroke volume or heart rate will result in corresponding increase or decrease in Blood pressure unless the other value changes as week. Ex increase SV leads to increase BP unless decrease HR
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What are the 4 variable that affect Stroke Volume (volume of blood pumped by a ventricle/ heart beat) ?
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preload, contractility, after-load, blood volume
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What is the term "preload" , that is one of the variable affecting stroke volume?
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the effect of stretching Cardiac muscle cells, they are the factors that come before you load up the ventricles with blood
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What is the "frank-starling Law of the Heart"?
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the greater the volume of blood in the ventricle , the greater the stretch of the myocardium ,and the stronger the contraction, which will effect the volume of blood ejected during the next ventricular sytole
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What is preload affected by?
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anything that affects venouse return during the relaxation period
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what is venous return?
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volume of blood returning to the heart during the relaxation period
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What are examples of factors that could increase your preload?
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exercise, stress, IV
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Finish the following sentence: If increased preload, Increased ______, increased __________, increased BP unless you _______
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stroke volume, cardiac output,decrease heart rate
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What does preload depend on?
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volume of blood entering the ventricles (end diastolic volume)
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what is contractility?
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the strength of contraction of the cardiac muscle
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what is contractility directly related too?
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directly related to preload, the amount of stretch of the cardiac muscle cells
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What is the relationship between preload, stretch of myocardium, and strength of contraction?
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increased preload = increased stretch of myocardium = increased force of contraction (increased SV, increased CO, increased BP)
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What is the effect of an +Inotropic?
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increases contractility,
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What are + inotropes stimulated by?
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sympathetic nervouse system, epinepherine, Digoxin, Digitalis, Ca+2,
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What are the effects of " - intropes"?
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decrease contractility,
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What stimulates "- inotropes"?
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Parasympathetic NS, AcH, anoxia, acidosis, Ca+ channel blockers
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What is "afterload"?
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factors that come after the blood leaves the heart (after the ventricles) , ex. arteries, arterioles,capillary networks
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What is happening when there is "resistance to blood flow"?
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something is preventing the blood to get to the arteries
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What does circulation and body defense depend on?
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resistance to blood flow in the arteries and arterioles, both of which affect arterial blood pressure
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What is arterial blood pressure?
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pressure the ventricles must exert to open aortic and pulmonary semilunar valves
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What can arterial BP affect?
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affects both systolic and diastolic BP
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An increased resistance to blood flow , then increased afterload, results in a decreased Stroke volume, unless what occurs?
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unless there is an increased contractility (due to increased preload) and increased Heart Rate to maintain cardiac output and Blood pressure
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What the average total blood volume for woman?
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4-5 L
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What is the average total blood volume for men?
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5-6 L
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What is the diagnosis if someone has a ; decreased Blood Volume wich leads to decreased Preload which will decrease stroke volume and Cardiac output and Blood pressure
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hypotension
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What are the effects of decreased Blood Volume?
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if decreased blood volume, then decreased preload, which will decrease SV, and decreased CO, and decreased BP
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what are the effects of an increased Blood Volume?
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if increased blood volume, then increased preload, which will increase stroke volume, which will increase cardiac output and blood pressure.
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What are example of causes of increased blood volume?
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over-hydration by IV fluids
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What sets the basic rhythm of the heart beat?
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SA node (pacemaker) is influenced by several factors:
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what part of the brain contains cardiovascular centers?
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Medulla Oblangata
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What does the cardiovascular system receive input from?
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Limbic system, proprioceptors, chemo-receptors,baroreceptors
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What is the main function of baroreceptors?
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detect changes in blood pressure
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Where does the Sympathetic NS send signals to?
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Cardioacceleratory Center of medulla
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Where do the signals travel next from the : sympathetic NS --> cardioacceleratory center of medulla -->
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Nor-epinephrine
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Where do the signals travel next ? sympathetic NS --> Cardioacceleratory center of medulla --> Nor-epinephrine -->
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SA node
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Where do the signals travel next in the Autonomic NS: sympathetic NS --> Cardioacceleratory center of medulla --> Norepinephrine --> SA node -->
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increased heart rate
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Explain the path of the Autonomic nervous system when heart rate is increased
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sympathetic NS --> Cardioacceleratory center of Medulla --> Norepinephrine --> SA nodes --> increased heart rate
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How does +chronotropic affect the heart rate?
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increases it
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how do - chronotropic affect the heart rate?
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decreases heart rate
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what are example of +chronotropic drugs?
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epinephrine/ nor-epinephrine,
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What are examples of -chronotropic drugs?
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Beta blockers
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How does the autonomic NS decrease the heart rate?
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parasympathetic NS sends signals to --> cardioinhibitory center of medulla --> Vagus nerve releases ACh --> SA node --> decreased heart rate
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What harmones increase Heart rate?
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Epinephrine/norepinephrine , thryroid gland
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Where is epinephrine and nor-epinephrine produced?
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adrenal medulla
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What Ions increase Heart rate?
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Ca+, Na+, k+
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How does Ca+ increase heart rate?
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increases contractability
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How does Na+, K+ increase heart rate?
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affect action potential, therefore affect heart rate
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How does O2 and CO2 affect the heart rate?
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decreased amount of O2 increases heart rate, increased amount of CO2 increases heart rate
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How does Ph affect the heart rate?
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decreased pH causes increased Heart rate
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How does age affect the heart rate?
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increased age = decreased heart rate
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How does body temperature affect the heart rate?
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increased temperature= increased heart rate
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How does being physically fit affect heart rate?
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increased fitness leads to decreased heart rate, exercise in that moment leads to increased heart rate
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